var AddFrameAround = function (tank) {
    var oRender = tank.render;
    tank.frameAroundEnabled = true;
    tank.render = function (drawEngine) {
        oRender.apply(this, [drawEngine]);
        if (!this.frameAroundEnabled) return;

        var context = drawEngine.ctx;

        // draw outside rectangle
        context.beginPath();
        context.rect(this.x - 10, this.y - 10, this.width + 20, this.height + 20);
        context.lineWidth = 1;
        context.strokeStyle = 'yellow';
        context.stroke();
    };
    return tank;
};